Study Objectives:
- Differentiate between NSTEMI and STEMI in terms of pathophysiology, clinical presentation, and ECG findings.
- Describe the initial management of ACS, including pharmacotherapy and indications for invasive strategies.
- Discuss the principles of risk stratification and secondary prevention measures following an ACS event.
- Review the current guidelines on the management of NSTEMI and STEMI.
Study Outline:
Acute coronary syndrome (ACS) includes unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI), all associated with acute myocardial ischemia.
Management and diagnosis of ACS necessitate an understanding of its clinical presentation, epidemiology, pathophysiology, and evidence-based treatment approaches.
Clinical Presentation:
– Common symptoms: chest pain (pressure, tightness, squeezing sensation), possibly radiating to arms, neck, jaw, or back.
– Other symptoms: dyspnea, nausea, vomiting, diaphoresis, syncope.
– Atypical presentations: epigastric discomfort, unexplained fatigue, shortness of breath, especially in elderly, women, and diabetics.
Epidemiology and Pathophysiology:
– ACS is a major cause of morbidity and mortality globally.
– Risk factors: age, male sex, hypertension, dyslipidemia, diabetes, smoking, obesity, family history of coronary artery disease.
– Pathophysiology involves atherosclerotic plaque rupture or erosion, leading to thrombus formation and artery occlusion, causing myocardial ischemia and necrosis.
Clinical History and Examination:
– Focus on chest pain characteristics, duration, precipitating factors, and associated symptoms.
– Assess hemodynamic stability, heart rate, blood pressure, signs of heart failure or cardiogenic shock, cardiac murmurs, and pulmonary edema.
Differential Diagnosis:
– Includes pericarditis, aortic dissection, pulmonary embolism, esophageal disorders, musculoskeletal pain.
Investigations:
– Initial tests: 12-lead ECG (may show ST-segment elevation, T-wave inversion, new left bundle branch block), cardiac biomarkers (troponins).
– Additional tests: chest X-ray, echocardiography, coronary angiography (if needed).
Management:
– Pharmacologic therapy: antiplatelet agents (aspirin, P2Y12 inhibitors), anticoagulants (heparin, low molecular weight heparin), beta-blockers, ACE inhibitors, statins.
– Invasive strategies: percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), based on clinical risk scores, patient characteristics, and coronary artery disease extent.
Complications and Preventative Strategies:
– Complications: arrhythmias, heart failure, recurrent ischemia, bleeding from anticoagulation.
– Preventive strategies: control of risk factors, lifestyle modifications, adherence to secondary prevention medications.
For further reading and references, refer to the Cardiology Course (under Materials).
